Mathematics, 14.02.2020 19:32 erenackermanlevijaeg

Suppose the length of telephone calls form a normal distribution with a mean length of 8.0 min and a standard deviation of 2.5 min. The probability that telephone call selected a random will last more than 15.5 min is most nearly

(A) 0.0013
(B) 0.0026
(C) 0.2600
(D) 0.9987

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Answer from: sydc1215

(A) 0.0013

Step-by-step explanation:

Problems of normally distributed samples are solved using the z-score formula.

In a set with mean $\mu$ and standard deviation $\sigma$ , the zscore of a measure X is given by:

$Z = \frac{X - \mu}{\sigma}$

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.

In this problem, we have that:

$\mu = 8, \sigma = 2.5$

The probability that telephone call selected a random will last more than 15.5 min is most nearly

This is 1 subtracted by the pvalue of Z when X = 15.5.

$Z = \frac{X - \mu}{\sigma}$

$Z = \frac{15.5 - 8}{2.5}$

Z = 3

Z = 3 has a pvalue of 0.9987

1 - 0.9987 = 0.0013

So the correct answer is:

(A) 0.0013

Answer from: Quest

answer: a video game has three difficulty levels: easy, medium, and expert. the game's scoring works in such a way that a player has to score a fixed number of points to advance to the next level, and then the scoring starts over. the total score needed to clear all three difficulty levels is 7,500. two times the number of points needed to clear the easy level is 500 more than the number of points needed to clear the medium level. twice the number of points needed to clear the medium difficulty level is 1,500 more than the number of points needed to clear the expert level. if x, y, and z represent the easy, medium, and expert levels, respectively, and a is the coefficient matrix of the system of equations modeling this situation, identify the inverse matrix, a-1, and the solution matrix, x, of the system of equations.

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Answer from: Quest

Aye i really don’t know this but i need more point so i am guessing it’s c. 2.0or you can use other apps to you get the answer
The graph shows a distribution of data.what is the standard deviation of the data? a)0.5b)1.5c)2.0d)

The graph shows a distribution of data.what is the standard deviation of the data? a)0.5b)1.5c)2.0d)

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Suppose the length of telephone calls form a normal distribution with a mean length of 8.0 min and a...

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